Effects of interaural speech-recognition differences on binaural advantage for speech in noise.

The relationship between interaural differences in speech-recognition performance and binaural advantage for speech in noise was studied. Subjects were five hearing-impaired listeners with symmetrical pure-tone air-conduction audiograms and significant interaural differences in speech recognition. All subjects repeated nonsense syllables in the presence of competing noise in monaural and binaural conditions. Binaural advantage was calculated as the difference in signal-to-noise ratio that afforded 50 percent correct performance between the monaural and binaural conditions. The results were diverse. Although the majority of the subjects retained some degree of binaural advantage, a conclusive relationship between interaural differences in speech recognition and binaural advantage could not be established. The implications for binaural hearing aid fittings are discussed.